1. Field of the Invention
The present invention is generally related to a drain plug warning system and, more particularly, to a warning system that provides a magnetically actuated switch that is activated when a removable plug is in its proper location to close an aperture used to drain water from a watercraft.
2. Description of the Prior Art
Many different types of watercraft are provided with drain plugs to empty water from the craft after use. Drain plugs are provided for several types of watercraft, such as boats and personal watercraft. When the drain plug is removed, an aperture is opened through a wall of the watercraft, such as the transom. Typically, the aperture is located near the bottom of the watercraft to allow draining of water from the hull structure.
Unfortunately, an operator can occasionally forget to replace the drain plug prior to reusing the watercraft. If this occurs, water can rush through the opening in the transom when the watercraft is placed into the water. This will flood the hull of the watercraft and can cause it to sink and be subject to severe damage.
U.S. Pat. No. 4,542,373, which issued to Hillock on Sep. 17, 1985, discloses a small craft plug detector. The detector indicates whether a drain plug of a small boat or craft is installed. In one embodiment, a hollow cylindrical housing has upper and lower ends with central openings therethrough. An indicating plunger disposed within the housing has a rod which extends upwardly through the hole in the upper end of the housing and the lower end which extends downwardly through the opening in the lower end of the housing. A spring biases the plunger in an upper direction. Electrical contacts are provided so that an electrical connection may be made to activate a lamp, alarm or the like when the plunger is moved downwardly. A second embodiment utilizes the electrical contacts of the first embodiment but has no central opening in the upper end of the housing, and the plunger has no rod portion extending therethrough. A third embodiment of the invention is similar to the first embodiment but does not include the electrical contacts.
U.S. Pat. No. 5,047,753, which issued to Birchfield on Sep. 10, 1991, describes a drain plug position indicator apparatus. The apparatus includes a plug detector mechanism mounted adjacent an interior surface of a drain plug aperture directed through a transom of a boat. The detecting means includes a spring-biased switch positionable from an extended position in the absence of a plug to a retracted position in the presence of a plug directed through the transom. The switch is cooperative with an audible member to effect alarm in the absence of the plug.
It is clearly beneficial to provide a warning system to indicate that a drain plug is not properly replaced to seal an aperture in the transom. U.S. Pat. No. 5,047,753, described immediately above, discusses several prior patents that also address this problem. Warning systems known by those skilled in the art have provided switches to detect the presence of a drain plug in the aperture through the transom or hull of a watercraft. However, drain plug warning systems known to those skilled in the art have several severe disadvantages. Typically, warning systems use switches with moving parts that can be mechanically jammed or made electrically inoperative because of corrosion. Furthermore, the area within a boat or personal watercraft where the aperture is provided through the transom is particularly subject to the accumulation of sand, seaweed and other types of debris. This accumulation of foreign matter can adversely affect the moving parts of the switches used in drain plug warning systems. It would therefore be significantly beneficial if a drain plug warning system could be provided which detects the absence of a drain plug from its proper position to seal an aperture and, in response, provides an alarm such as a horn when an attempt is made to operate the watercraft without the drain plug in its proper position, and whose mechanisms do not interfere with the flow of water and debris through the aperture.